StrataMX Backup: queue incoming mail while your server is unavailable
StrataMX Backup is our own developed and operated MX backup service. It accepts mail for configured recipients when your primary destination is unavailable, queues it within the agreed service limits and retries delivery when the destination recovers. It is ordered separately from SpamWeeder Premium, VIPRE and Proofpoint Essentials filtering.
Need webmail access during outages? → See StrataMail Email Continuity
StrataMX Backup: service specifications
| Feature | What you get |
|---|---|
| Service type | Our independent queue-and-redeliver service, also called backup MX or mail bagging. |
| Incoming delivery | A configured secondary MX or an agreed gateway delivery route sends mail to the backup queue when the primary destination is unavailable. |
| User mailbox access | No user inbox, IMAP mailbox or browser composer is included in this queue-only service. |
| Recovery | Accepted queued messages are retried to the configured destination within the selected plan's limits. |
| Filtering relationship | Separate from the native queues and browser continuity in SpamWeeder Premium, VIPRE and Proofpoint Essentials. Combining services requires an agreed routing design. |
| Need to read or send during an outage? | Compare our StrataMail Email Continuity mailbox service or the browser continuity in an eligible filtering plan. |
What StrataMX Backup Does
StrataMX Backup is a queue-and-redeliver service, sometimes called mail bagging or mail spooling. It is the safety net under your mail infrastructure — invisible during normal operation, active the moment something goes wrong.
When your primary mail server is unreachable — whether from a hardware failure, maintenance window, network outage, or ISP issue — sending servers normally retry temporary delivery failures. With StrataMX Backup configured, eligible incoming mail can be accepted into our separate relay queue and held for the published retention window. Delivery is retried to your primary destination when it becomes available; permanent rejections and expired messages still need attention.
What it is
- DNS secondary MX — lower-priority MX record for the domain
- Queue-and-redeliver — accepts, holds, and redelivers inbound mail after recovery
- 30-day relay queue retention
- 5-minute retry interval once primary recovers
- Compatible with any SMTP-reachable primary mail platform
- Per-domain pricing — no per-user fees
What it is not
- Not a webmail service — users cannot read or reply during an outage event
- Not a spam filter — SpamWeeder Premium is available as a separate add-on
- Not the primary MX — only activates when the primary is unreachable
- Not a shadow mailbox — no local copy stored for user access
If read and reply access during outage events is required, see StrataMail Email Continuity — which adds a shadow mailbox and branded webmail access on top of the relay queue.
How It Works
- Normal operation — Inbound mail flows to your primary mail server. StrataMX Backup is idle.
- Primary goes down — Sending mail servers detect that the primary MX is unreachable and automatically fall back to the lower-priority StrataMail MX record.
- StrataMX accepts eligible mail — Messages for configured recipients are accepted into the relay queue, subject to the agreed policies and service limits.
- Relay queue holds for up to 30 days — Mail is stored securely and retried every 5 minutes once the primary becomes reachable again.
- Primary recovers — StrataMail detects recovery and automatically flushes the relay queue. Accepted queued messages are retried to the configured primary destination; delivery failures still need administrator attention.
When StrataMX Backup Protects You
- Server hardware failure — disk failure, power issue, or component failure on your mail server
- Planned maintenance windows — server updates, migrations, reboots — schedule downtime without mail loss
- ISP or network outage — upstream connectivity failure between the internet and your mail server
- Data center incidents — power events, cooling failures, or facility issues affecting your server
- Microsoft 365 / Google Workspace disruptions — when the cloud platform itself has a service incident
- M365 tenant-to-tenant migrations — StrataMail catches inbound mail during the DNS propagation window when mail can arrive unpredictably at either tenant. Learn about M365 migration coverage →
- Hosting provider issues — cPanel, Plesk, or shared hosting environments experiencing outages
Supported Primary Mail Platforms
StrataMX Backup works with any SMTP-reachable primary mail server, including: Microsoft 365 (Exchange Online), Google Workspace (Gmail), Microsoft Exchange (on-premises), cPanel / WHM, Plesk, Zimbra, Postfix, Sendmail, Exim, Kerio Connect, and any SMTP-compatible mail platform.
Optional Add-On — SpamWeeder Premium
StrataMX Backup can be paired with separately ordered SpamWeeder Premium filtering. We agree and test the delivery route to our queue before cutover. SpamWeeder Premium's own delivery queue and browser continuity remain features of that filtering service; adding StrataMX Backup creates a separate queue service.
Adding SpamWeeder Premium means your inbound mail is filtered even during the backup MX window — queued messages were already scanned before being held in the relay queue. Learn about SpamWeeder Premium →
StrataMail Backup MX vs. Full Email Continuity
Not sure which product fits your situation? Here is the key difference:
| StrataMX Backup | StrataMail Email Continuity | |
|---|---|---|
| Mail queued during outage event | Yes | Yes |
| Mail redelivered on recovery | Yes | Yes |
| Webmail access during outage event | No | Yes — branded webmail |
| Read email during outage event | No | Yes |
| Reply and send during outage event | No | Yes |
| Shadow mailbox (local copy) | No | Yes |
| SpamWeeder Premium add-on available | Yes | Yes |
| Per-domain pricing | Yes | Yes |
| Best for | Queue protection — outage event is invisible to senders | Business continuity — users stay productive during outage event |
See full comparison → | See StrataMail Email Continuity →
Reseller & MSP Program
StrataMX Backup is built for resellers. MSPs, hosting providers, and IT consultants can add backup MX protection to every customer domain — under their own brand, with their own pricing, from a single reseller account.
- White-labeled admin control panel — your branding, your logo
- Per-domain provisioning — add and manage customer domains through the portal
- Usage dashboard — monitor domain status, relay queue depth, and relay activity
- Outage alerts — email and SMS notifications when a customer's primary goes down
- Branded alert emails — alerts sent from your address, not ours
- Volume pricing — deeper discounts at higher domain tiers
- Dedicated reseller support channel
Reseller tiers start at $29.99/month for up to 5 domains — effective $6.00/domain.
View Reseller Pricing → | Learn About the Reseller Program →
Direct Customer Pricing
Not a reseller? StrataMX Backup is available directly at a per-domain rate with no platform fee and no volume commitment.
- $12.00/domain/month — includes 30-day relay queue retention, monitoring, and outage alerts
- One-time setup fee: $125/domain
- SpamWeeder Premium add-on: +$9.00/domain/month
Protecting 5 or more domains? The reseller Starter tier at $29.99/month is a better value. See the comparison →
Get Backup MX pricing
Configure what you need and see the cost, or tell us your situation and we will scope it.
See Pricing Describe Your Challenge
